Is FoundationDB capable of integrating with FileMaker 15?
Not unless you write your own custom intermediary to push and pull data from it. EG a web API frontend for FoundationDB.
It is not compatible via ESS.
I don't think it supports ODBC either.
As it's a "noSQL" type of database, it is not compatible with very much in the database world we are most familiar with. It is non-relational and you can't use sql to access it.
Correct, how can be leverage something like FLOW:
Retrieving data ...